Study of the Tolerance Difference between Gram Positive and Gram Negative Bacteria to Potassium Sorbate

Abstract:

In this study,the tolerance of 3 gram positive(Bacillus cereus,Staphylococcus aureus and Listeria monocytologene) and 3 gram negative bacteria(Vibrio parahaemolyticus,Salmonella and Pseudomonas fluorescens) topotassium sorbate were carefully studied by pure cultivation and simulation of food system.When 1 g/L potassium sorbate was presented in culture,the number of gram negative bacteria was reduced to up to 2~3.5 lg(CFU/mL),while those of gram positive bacteria were only reduce to 1 lg(CFU/mL).This results demonstrated potassium sorbate inhibited on the gram negative bacteria growth than that of the gram negative bacteria.Results of pure culture,minimal inhibitory concentration(MIC) and inoculation to instant kelp results all showed that the tolerance of gram positive bacteria is better than gram negative bacteria.It may have significance in the application of potassium sorbate on the control of gram positive bacteria.